Search results for "germinal center"
showing 10 items of 41 documents
Abstract PO-35: Prognostic significance of MYC, BCL2, and BCL6 colocalization at single-cell resolution in DLBCL
2020
Abstract MYC, BCL2, and BCL6 are commonly used markers for immunohistochemistry of Diffuse large B-cell lymphomas (DLBCL). Coexpression of MYC and BCL2 in particular constitutes a subgroup of “double expressor lymphomas” (DEL) with a distinct poor clinical outcome. However, it is not known if MYC and BCL2/BCL6 coexpression occurs in the same cell or in different cells within the tumor, as traditional immunohistochemistry (IHC) is limited by the number of markers that can be simultaneously assessed within formalin-fixed, paraffin-embedded (FFPE) samples. We set out to discover the clinical significance of MYC, BCL2, and BCL6 colocalization at single-cell resolution using multiplexed quantita…
Gene Expression Analysis Uncovers Similarity and Differences Among Burkitt Lymphoma Subtypes.
2011
Abstract Abstract 2494 Background. Burkitt lymphoma (BL) is currently listed in the WHO classification of lymphoid tumors as a single genetic and morphological entity with variation in clinical presentation. In particular, three clinical subsets of BL are recognized: endemic (eBL), sporadic (sBL) and immunodeficiency associated (ID-BL). Each affects different populations and can present with different features. So far, possible differences in their gene expression profiles (GEP) have not been investigated. In this study we aimed to 1) assess whether BL subtypes present with differences in their GEP; 2) investigate the relationship of the different BL subtypes with the non-neoplastic cellula…
Nfatc1/Αa and Blimp-1 Support the Follicular and Effector Phenotype of Tregs
2021
CD4 + CXCR5 + Foxp3 + T follicular regulatory (T FR ) cells control the germinal center responses. Like follicular helper T-cells, they express high levels of N uclear F actor of A ctivated T -cells c1 , predominantly its short isoform NFATc1/αA. Ablation of NFATc1 in Tregs prevents upregulation of CXCR5 and migration of T FR cells into B-cell follicles. By contrast, constitutive active NFATc1/αA defines the surface density of CXCR5, whose level determines how deep a T FR migrates into the GC and how effectively it controls antibody production. NFATc1/αA is necessary to overcome T FR -expressed B l ymphocyte- i nduced m aturation p rotein (Blimp-1), which can directly repress Cxcr5. Blimp-1…
A20 deficiency in B cells enhances B-cell proliferation and results in the development of autoantibodies.
2011
A20/TNFAIP3 is an ubiquitin-editing enzyme, important for the regulation of the NF-κB pathway. Mutations in the TNFAIP3 gene have been linked to different human autoimmune disorders. In human B-cell lymphomas, the inactivation of A20 results in constitutive NF-κB activation. Recent studies demonstrate that in mice the germline inactivation of A20 leads to early lethality, due to inflammation in multiple organs of the body. In this report, we describe a new mouse strain allowing for the tissue-specific deletion of A20. We show that B-cell-specific deletion of A20 results in a dramatic reduction in marginal zone B cells. Furthermore, A20-deficient B cells display a hyperactive phenotype repre…
The Humoral Response in TCR α-/-Mice. Can γδ-T Cells Support the Humoral Immune Response?
2002
An optimal humoral response requires T-cell help; however, it has been questioned if this help comes exclusively from alphabeta-T cells or whether gammadelta-T cells also contribute. We have attempted to answer this question by studying the humoral response in T-cell receptor alpha-chain knockout (alpha-/-) mice, which lack the alphabetaT cell subset. Two model antigens were used to characterize the response: the thymus-independent (TI) antigen native dextran B512 (Dx), and the thymus-dependent (TD) antigen heat shock protein (HSP65) from Mycobacterium tuberculosis. When challenged with Dx, the alpha-/- mice elicited a strong antibody response and formed rudimentary germinal centres (GCs), …
In situ transcriptional profile of a germinal center plasmablastic burst hints at MYD88/CD79B mutants-enriched Diffuse Large B-cell Lymphomas
2021
AbstractThe germinal center (GC) reaction results in the selection of B-cells acquiring effector Ig secreting ability by progressing towards plasmablastic differentiation. This transition is associated with exclusion from the GC microenvironment. The aberrant expansion of plasmablastic elements within the GC fringes configures an atypical condition, the biological characteristics of which have not been defined yet. We investigated the in situ immunophenotypical and transcriptional characteristics of a non-clonal germinotropic expansion of plasmablastic elements (GEx) occurring in the tonsil of a young patient. Compared to neighboring GC and peri-follicular regions, the GEx showed a distinct…
IgG Fc sialylation is regulated during the germinal center reaction following immunization with different adjuvants
2020
Background: Effector functions of IgG Abs are regulated by their Fc N-glycosylation pattern. IgG Fc glycans that lack galactose and terminal sialic acid residues correlate with the severity of inflammatory (auto)immune disorders and have also been linked to protection against viral infection and discussed in the context of vaccine-induced protection. In contrast, sialylated IgG Abs have shown immunosuppressive effects.Objective: We sought to investigate IgG glycosylation programming during the germinal center (GC) reaction following immunization of mice with a foreign protein antigen and different adjuvants.Methods: Mice were analyzed for GC T-cell, B-cell, and plasma cell responses, as wel…
Is minor salivary gland biopsy more than a diagnostic tool in primary Sjorgren's syndrome? Association between clinical, histopathological, and molec…
2014
Objectives: Several histological scoring systems, including the focus score, performed in minor salivary glands (MSGs) by hematoxylin-eosin (H&E) staining, have been employed in clinical practice to assess the inflammatory infiltrate and provide the diagnosis of primary Sjorgren's syndrome (pSS). Aims of this study were to integrate different scoring systems and identify potential differences in the molecular profile of lymphoid cytokines related to germinal center (GC) formation and clinical subsets in pSS. Methods: Overall, 104 pSS patients and 40 subjects with sicca non-pSS were retrospectively evaluated. MSG biopsies were evaluated by H&E and immunofluorescence to assess histological pa…
The interleukin (IL)-31/IL-31R axis contributes to tumor growth in human follicular lymphoma
2014
Interleukin (IL)-31A binds to an heterodimer composed of IL-31 receptor A (IL-31RA) and Oncostatin M Receptor (OSMR). The IL-31/IL-31R complex is involved in the pathogenesis of various skin diseases, including cutaneous T-cell lymphoma. No information is available on the relations between the IL-31/IL-31R complex and B-cell lymphoma. Here we have addressed this issue in follicular lymphoma (FL), a prototypic germinal center(GC)-derived B-cell malignancy. IL-31 enhanced primary FL cell proliferation through IL-31R-driven signal transducer and activator of transcription factor 1/3 (STAT1/3), extracellular signal-regulated kinase 1/2 (ERK1/2) and Akt phosphorylation. In contrast, GC B cells d…
The neuroimmune connection in human tonsils.
1991
The present light microscopic immunohistochemical study evaluates the distribution of peptidergic nerve fibers in human tonsil and describes their spatial relationship with specific cells of the immune system. Further, using a panneural marker protein gene product (PGP) 9.5, a qualitative evaluation of the density of specific peptidergic innervation of the human tonsil was performed. Nerve fibers staining for tachykinins, calcitonin gene-related peptide, neuropeptide Y, or vasoactive intestinal polypeptide/peptide histidine isoleucine showed characteristic distribution patterns, but constituted only a minor subfraction of the PGP 9.5-stained fiber population. Both peptide- and PGP 9.5-immun…